Effects of sprint interval training on markers of metabolic health: A three-level meta-analysis of randomised controlled trials.

In 30 seconds

This systematic review and three-level meta-analysis examined randomised controlled trials comparing sprint interval training (SIT) with no-exercise control or moderate-intensity continuous training (MICT) for metabolic health. Forty trials involving 1,460 participants were included. Compared with no exercise, SIT improved glycemic, insulin-response, and lipid-related outcomes, although results were heterogeneous and some estimates were sensitive to analytic choices. At the outcome-domain level, SIT did not differ significantly from MICT. Evidence certainty was low to very low, so the findings warrant cautious interpretation.

Key findings

• Across 40 trials and 1,460 participants, SIT improved glycemic, insulin-response, and lipid-related outcomes versus no-exercise control.
• Outcome-specific analyses favored SIT over no exercise for fasting insulin, HOMA-IR, LDL-C, and total cholesterol.
• SIT and MICT showed no significant differences at the outcome-domain level; HOMA-IR favored SIT in an outcome-specific comparison.
• Health condition moderated glycemic outcomes, while measurement type and exercise modality moderated lipid-related outcomes.

Why it matters

The findings suggest that SIT may offer metabolic benefits compared with inactivity and broadly comparable effects to MICT, informing consideration of different exercise approaches. However, substantial heterogeneity, sensitivity of some estimates, and low-to-very-low evidence certainty limit confidence in the size and consistency of these effects.

What to keep in mind

The evidence had substantial to considerable heterogeneity, some estimates were sensitive to study or effect-size removal, and certainty was low to very low.